The present invention relates, in general, to backing plates on brake shoes for railway vehicles, i.e. railway cars and locomotives, as well as backing plates for disc pads for railway and automotive applications and, more particularly, this invention relates to polymer based backing plates as a replacement for the steel plates presently in use.
Backing plates have been used for countless years to attach a brake shoe to a brakehead. Brake shoes, be they steel shoes, wooden shoes or the variety of composition shoes used throughout the railroad industry, are mounted or bonded onto a backing plate. This unit is then connected to a brakehead. Through the years the industry has seen many improvements in backing plates. Most of these improvements have been concerned with more securely mounting the backing plate and thus the brake shoe to the brakehead.
Various lug arrangements, anchoring tongues and a variety of modifications have been employed to more firmly anchor the backing plate to the brakehead. However, through all of the years there has not been any changes in the composition of backing plates. That is, backing plates, used with composition brake shoes, have been and still are formed from metal. Generally, if not always, the metallic material used to make these backing plates is steel. By using steel the backing plates incur all the advantages and also the disadvantages which are inherent with this material.
The present invention provides, in a first embodiment thereof, a lightweight backing plate for use with at least one of a railway brake shoe and a disc brake pad. The lightweight backing plate being formed from a predetermined polymeric material selected from a group consisting of unsaturated polyester, polyphenylene sulfide, glass epoxy, phenolic polymers and various mixtures thereof.
In a second embodiment, the present invention provides a composition brake shoe for use with at least one of railway vehicle brakes and automotive brakes. The brake shoe comprises a lightweight backing plate which is formed from a predetermined polymeric material selected from a group consisting of unsaturated polyester, polyphenylene sulfide, glass epoxy, phenolic polymers and various mixtures thereof. The brake shoe further includes a preselected friction type composition material having a predetermined shape. The friction type composition material being bonded to the lightweight backing plate.
According to a third embodiment of the invention there is provided a method of manufacturing an improved brake block for use with at least one of railway brake shoes and disc brake pads. The method comprises the steps of selecting a composition friction material. Molding the composition friction material, at a predetermined temperature and a predetermined pressure, to form a predetermined shape for use as at least one of a brake shoe and a brake pad. Selecting a polymeric material from a group consisting of unsaturated polyester, polyphenylene sulfide, glass epoxy, phenolic polymers and various combinations thereof. Forming a backing plate from the preselected polymeric material into a predetermined configuration and bonding the composition friction material to the backing plate.
It is, therefore, one of the primary objects of the present invention to manufacture a backing plate from a preselected polymeric material.
Another object of the present invention is provide a backing plate which will generally extend the useable life of a brake shoe.
It is still another object of the present invention to provide a lightweight backing plate that will be substantially easier to manufacture.
Yet another object of the present invention is to provide a lightweight backing plate which will be less expensive to produce than presently used backing plates.
An additional object of the present invention is to provide a method of forming a backing plate that can be made in situ during molding of the friction materials.
These and various other objects and advantages of this invention will become apparent after a full reading of the following detailed description, particularly, when read in conjunction with the attached drawings as described below and the appended claims.